patch 8.2.0274: hang with combination of feedkeys(), Ex mode and :global

Problem:    Hang with combination of feedkeys(), Ex mode and :global.
            (Yegappan Lakshmanan)
Solution:   Add the pending_exmode_active flag.
diff --git a/src/globals.h b/src/globals.h
index bda75b4..fc551ba 100644
--- a/src/globals.h
+++ b/src/globals.h
@@ -1028,6 +1028,10 @@
  * Ex mode (Q) state
  */
 EXTERN int exmode_active INIT(= 0);	// zero, EXMODE_NORMAL or EXMODE_VIM
+
+// Flag set when main_loop() should exit when entering Ex mode.
+EXTERN int pending_exmode_active INIT(= FALSE);
+
 EXTERN int ex_no_reprint INIT(= FALSE); // no need to print after z or p
 
 EXTERN int reg_recording INIT(= 0);	// register for recording  or zero